<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
</head>
<body>
	<form action="">
		<p>选择城市：</p>
		<p>		
		<select name="" id="s1">
			<option value="beijing" >beijing</option>
			<option value="shanghai">shanghai</option>
			<option value="taiyuan">taiyuan</option>
		</select>

</p>
<h2>please sure your select name: <span id='s2'>taiyuan</span></h2>

	</form>
</body>
<script type="text/javascript">
	s1obj=document.getElementById('s1');
	s2obj=document.getElementById('s2');
	s1obj.onchange=function(){
		s1val=this.value;
		s2obj.innerHTML=s1val;

	}
</script>
</html>